Potential Benefits and Risks of Mammograms

Why may mammograms be more beneficial in women aged 50 and older than women under age 50?

The answer to this question is not clear. It may be because younger women more commonly have dense breast tissue that can hide breast cancer and make it hard for mammograms to detect. Or it might be because breast cancer in young women tends to grow more quickly and spread early so that mammograms don't find the breast cancer until after it has spread and become incurable. Also, since breast cancer is less common in younger women, there are fewer potential breast cancer deaths to prevent.

References:
Kerlikowske K, Grady D, Barclay J, Sickles EA, Ernster V. Effect of age, breast density, and family history on the sensitivity of first screening mammography. JAMA 1996;276:33-38.
Porter PL, El-Bastawissi AY, Mandelson MT, Lin MG, Khalid N, Watney EA, et al. Breast tumor characteristics as predictors of mammographic detection: comparison of interval- and screen-detected cancers. J Natl Cancer Inst. 1999;91:2020-8.

Potential Benefits & Risks of Mammograms